<-- Those are cells, they're inoffensive, infect them to spread faster :)
but beware, antibodies are here !
Play
<-- This is an antibody, it'll try to eliminate you
You can multiply your parasite by infecting many cells at once
PlayMoving to adjasent cell duplicate your parasite.
Jumping cell move the parasite without duplication!
PlaySome environments can affect the longevity of the parasite, they'll degrade it slowly since it die.
In such environments, your parasite will have two indicators :

Defend the entry point
PlayAttack both sides
PlayCongratulations you've finished the 30 levels.
New levels are in preparation with new mutations and cells, and will be released soon.